Endogenous ET-1 contributes to liver injury induced by galactosamine and endotoxin in isolated perfused rat liver

Injury to hepatocytes most likely occurs via disturbances in the microcirculation. The role of vasoconstriction due to the effect of endogenous endothelin-1 (ET-1) in the development of galactosamine (GalN)- and lipopolysaccharide (LPS)-induced liver injury was investigated. Using the multiple indicator dilution technique, we measured the volume of the hepatic sinusoids and the apparent Disse space as indicators of overall hepatic microcirculation. Serum purine nucleoside phosphorylase activity as a marker of damage to nonparenchymal cells increased and the volume of the sinusoids and the Disse space decreased prior to hepatocyte damage in rats treated intraperitoneally with GalN and LPS. Moreover, the amount of ET-1 release was elevated. When livers from untreated rats were perfused with ET-1 in a recirculating system, hepatocyte damage was observed similar to experiments with GalN and LPS. A monoclonal anti-endothelin antibody, AwETN40, diminished the extent of liver injury caused by GalN and LPS in isolated perfused rat liver. The present study suggests that vasoconstriction is an early event in GalN- and LPS-induced liver injury and that the development of hepatocyte damage is mediated via microcirculatory disturbances due to endogenous ET-1.